Process for the production of catalysts with improved accessibility

Abstract

The present invention is directed to a process for preparing a catalyst which comprises combining catalyst components or precursors thereof in an aqueous medium to form a catalyst precursor mixture, feeding the mixture to a shaping apparatus, and shaping the mixture to form particles wherein just before the shaping step the mixture is destabilized. It was found that with this process catalysts can be prepared which have both a good attrition resistance and a high accessibility. The invention further relates to catalysts obtainable by this process.

1. A process for preparing a catalyst which comprises combining catalyst components or precursors thereof in an aqueous medium to form a catalyst precursor mixture, feeding the mixture to a shaping apparatus, and shaping the mixture to form particles, said mixture being destabilized less than about 300 seconds before the shaping step. 
     
     
       2. The process of  claim 1  wherein shaping is performed by spray-drying, extrusion, pelletizing or beading. 
     
     
       3. The process of  claim 1  wherein the catalyst is an FCC catalyst. 
     
     
       4. The process of  claim 3  wherein the shaping is performed by spray-drying. 
     
     
       5. The process of  claim 1  wherein the catalyst precursor mixture comprises aluminium chlorohydrol or an aluminium chlorohydrol-containing composition. 
     
     
       6. The process of  claim 5  wherein the aluminium chlorohydrol-containing composition has been produced by reacting aluminium trihydrate or its thermally treated form with HCl. 
     
     
       7. The process of  claim 5  wherein destabilization is performed by decreasing the pH to below about 3.5 or increasing the pH to above about 4.5. 
     
     
       8. The process of  claim 1  wherein the catalyst precursor mixture comprises a nitric acid based alumina sol. 
     
     
       9. The process of  claim 8  wherein the nitric acid based alumina sol has been produced by reacting aluminium trihydrate or its thermally treated form with HNO 3 . 
     
     
       10. The process of  claim 1  wherein an acid or base stream is added to promote destabilization. 
     
     
       11. The process of  claim 1  wherein the catalyst precursor mixture comprises water glass and/or a silica sol which may or may not be sodium-free. 
     
     
       12. The process of  claim 11  wherein destabilization is performed by increasing the initial pH, which is in the range of about 1 to about 5, to a destabilization pH in the range of about 3-10. 
     
     
       13. The process of  claim 12  wherein destabilization is performed by increasing the pH from about 2.5-3.5 to between about 4-6. 
     
     
       14. The process of  claim 11  wherein the catalyst precursor mixture comprises peptised alumina. 
     
     
       15. The process of  claim 11  wherein destabilization is performed by changing the temperature from about 15-35° C. to about 40-99° C. 
     
     
       16. The process of  claim 1  wherein the catalyst precursor mixture comprises peptised alumina. 
     
     
       17. A process according to  claim 16  wherein destabilization is performed by decreasing the initial pH, which is in the range of about 3 to 5, to a destabilization pH of about 4 or higher. 
     
     
       18. The process of  claim 16  wherein destabilization is performed by changing the temperature from about 15-35° C. to about 40-99° C. 
     
     
       19. The process of  claim 1  wherein destabilization is performed by changing the temperature from about 15-35° C. to about 40-99° C. 
     
     
       20. The process of  claim 1  wherein said catalyst precursor mixture is destabilized by changing the pH by the addition of a pH regulating agent. 
     
     
       21. The process of  claim 20  wherein the pH regulating agent is sodium hydroxide, ammonium hydroxide, nitric acid, sodium aluminate, magnesium oxide, sodium silicate, silica sol, sodium phosphate, ammonium phosphate and/or diammonium phosphate. 
     
     
       22. The process of  claim 20  wherein the pH regulating agent is a phosphate treated zeolite and/or a mixture of phosphate and zeolite, anionic clay and/or doped anionic clay. 
     
     
       23. The process of  claim 22  wherein the pH regulating agent is anionic clay or doped anionic clay, said anionic clay being stabilized by hydrothermal treatment or being prepared under hydrothermal conditions.